Typewriter escapement mechanism



United States PatentQ TYIEWRITER ESCAPEMENT MECHANISM John E. Finch, Sn, Jersey City, N. J.

Application November 25, 1953, Serial No. 394,402

6 Claims. (Cl. 197-88) This invention relates to typewriter escapement mechanism, .and more particularly to the escapement mechanism for the carriage therefor.

It is an object of the present invention to provide a typewriter escapement to work in conjunction with my copending application Serial No. 394,403, filed November 25, 1953, to reduce carriage vibration While the typewriter is in operation.

Another object of my invention is to provide means for reducing jarring of a typewriter carriage during its operation, and also to prevent undue vibration of the carriage in its movement relatively of the typewriter body during typewriting operation, and thereby to improve horizontal alignment of type characters.

Other objects and features of my invention will become apparent from the following detailed description taken in conjunction with the accompanying drawing, wherein:

Fig. 1 is a detail fragmental, broken away rear elevation view of an escapement assembly in a typewriter incorporating my invention; I

Fig. 2 is a fragmental, broken away sectional elevation view showing a part thereof in operation;

Fig. 3 is a detail View taken on line 33 of Fig. l; and

Fig. 4 is a perspective view of the adjusting screw as used in Fig. 1.

Referring now to the drawings illustrating a preferred embodiment of my invention and wherein like numbers refer to like parts throughout, I show a rack and a pinion 11, such rack forming part of the carriage in the usual or conventional typewriter. The pinion 11 is mounted on a shaft 12 onto which is also mounted an escapement wheel 13 having teeth 14.

A dog rocker or escapement plate 15 is pivotally mounted between a supporting frame 1616 forming a part of the escapement mechanism.

The rocker 15 is moved about pivots 1717 when the dog rocker 15 is actuated by typewriter key or space bar mechanism, not shown.

Said rocker has an escapement plate drop adjusting lug 13 near its top 19 which has a threaded opening for accommodating a drop adjusting screw 20.

The rocker top 19 is also provided with a fixed dog or roller bearing 21, adapted to abut against the teeth 14 of wheel 13 on pivotal movement of the rocker 15. Said rocker is also provided with a loose or stepping dog 26 which is pivoted upon a shoulder screw 22 which is projected through and secured to rocker 15 near its center.

The loose dog 26 is also adapted to abut, at its upper curved tip 23 against the teeth 14 of the wheel 13 on return of the rocker 15 and its rigid dog or roll 21 from arresting control of a tooth 14 of the escapement wheel 13, and at a lower point 30 and on its reverse part against the limit screw 2% The rocker 15 has a side extending member or car 24, with an opening therein to retain one end of a spring 25. Said stepping dog 26 is pivoted to the rocker and has an 2,777,557 Patented Jan.*15, 1957 datingthe other end of spring 25.

A stop 33 is provided on the rocker 15 to limit the pivotal-movement of the dog26 against the spring action of spring 25 in time for the loose dog 26 to arrest movement of Wheel 13 by engaging a succeeding escapement wheel tooth 14, after its release from rigid dog 21 by rocker actuation.

it is at theinstant that the loose dog 26 limits upon the drop adjusting screw 20 that the major impact shock takes place during the typewriter operation, as the carriage, impelled by main spring pull transmitted through the carriage draw-band, not shown, abruptly loses its tem- Porary freedom from the holding action.

The loose dog 26 has heretofore limited upon the drop adjusting screw 20, fiat surface to flat surface, in what might be called a head-on collision with resultant recoil. The important feature of this invention, as shown, is that the drop limit adjusting screw 20, which for evident reasons must be made slightly longer than previously, is cut at its free end forming an oblique horizontal section 28, which forms sliding contact with the obliquely cut away section 29 in the upper part 30 of loose dog 26.

In my invention the loose or stepping dog 26 has that section of its back part 29 which limits or beds upon a screw 24 or plate or abutment in or upon an escapement dog rocker, placed to limit drop, and opposite to that side of the loose dog which contacts escapement wheel teeth, shaped at an oblique horizontal angle, and the screw end 28, plate or abutment upon which it limits ground to a corresponding angle, about 60 viewed from the front, to conform with each other, so that the shock of contact on operation of the typewriter will be greatly dissipated or absorbed.

In a typewriter using a screw 20 for drop adjustment, and having the loose dog 26 limit upon its obliquely cut threaded end 28, adjustment may be made, one full turn of screw 20, in or out, by holding a key lever or space bar depressed during screw turning adjustment so that loose dog 26 is free from contact with adjusting screw 20.

A position marker 31 is provided as shown in Fig. 4 on the head 32 of screw 2% so that the obliquely cut screw end is retained in alignment after completion of screw adjustment with the obliquely shaped back section of loose dog 29 with which it comes in contact during typewriter operation.

While a preferred embodiment of my invention has been illustrated and described, it is to be understood that changes as to form, arrangement of parts and the use thereof may be made without departing from the spirit and scope of my invention as claimed herein.

What I claim is:

1. In a typewriter machine, the combination with a rack and pinion gear and an escapement wheel, of a tiltable dog rocker, a fixed dog member on the rocker for contact with the teeth of the escapement wheel, a tiltable member on the rocker for making alternate contact with said teeth, said tiltable member having its upper end provided with an inclined cutaway portion, and adjustable means on the rocker forming contact with the tiltable member, said adjustable means having an inclined face to make contact with the cutaway portion of the tiltable member.

2. In a typewriter machine, an escapement assembly for preventing jarring and vibration of the machine, comprising a rack and pinion, an escapement wheel, a tiltable dog rocker, fixed means on the rocker adapted to make contact with said wheel when the rocker is in one position, adjustable screw means on the rocker having a terminal inclined cutaway portion, and a tiltable member pivoted to the rocker having an upwardly extending end adapted to make contact with the wheel when the rocker in in another position, said tiltable member having a recessed 7 inclined face portion at the upwardly extending end thereof adapted to make contact with the inclined terminal portion of the screw means to reduce the jarring of the machine carriage when in use.

3. In a typewriter machine and the like, an escapement mechanism including a rack and pinion, an escapement ment wheel, an adjustable screw member on said dog rocker extending horizontally thereof, a loose dog member pivoted to the rocker being in substantially thesame pla ne as the screwmember and tensioned means on the rocker connected with one end of the loose. dog memben said screw member having an oblique terminal section, and

said loose dog member having an upper section adapted to form contact with the teeth of the escapement wheel and having an inclined oblique portion for abutting contact with the oblique terminal section of the screw I member.

' 4.'In a typewriter machine, an escapement mechanism according to claim 3 wherein the adjustable screw member a is disposed so that-its oblique terminal section is in a face to face position relatively to the oblique portion of the loose dog member.

5. In a typewriter machine, an escapement mechanism according to claim 4 wherein the loose dog member is in a vertical plane parallel with the fixed dog member and is adapted to alternately contact the teeth of the escapement wheel with respect to the fixed dog member and to reduce jarring of the typewriter carriage when said loose dog member makes contact with the adjustable screw member.

6. A typewriter escapement mechanism according to claim 4 wherein the loose dog member has a curved free upper terminal portion with a horizontally oblique section short of the terminal portion adapted to make contact with the terminal section of the adjustable screw member.

References Cited in the file of this patent UNITED STATES PATENTS 

